Auxiliary motor control unit



c. c. DUCHAUSSOY AUXILIARY MOTOR CONTROL UNIT 2 Sheets-Sheet 1 Filed Feb. 24, 1948 Aug, 23 149. i c. c. DucHAussoY J 2,479,734

AUXILIARY MOTOR CONTROL UNIT Filed Feb. 24, 1948 2 Sheets-$heet 2 SI'VUW omiile Charles Duchuussoy Atrornevs Patented Aug. 23,}949

AUXILIARY MOTOR CONTROL UNIT Camille Charles Duchaussoy, Saint-Maur, France,

assignor to Compagnie Generale Pour LEquipment Aeronautique, Societe Anonyme, Paris, France, a corporation of France Application February 24, 1948, Serial No. 10,528 In France April 4, 1944 Section 1, Public Law 690, August 8, 1946 Patent expires April 4, 1964 6 Claims.

The present invention relates to control devices comprising clutches, and more particularly to emergency controls for an auxiliary motor drive of a rotating shaft which is normally driven by a principal motor, the auxiliary motor being thrown in only in case of stoppage of the principal motor.

Such installations are frequent in machines where there are employed an auxiliary electric motor, for example, to start an internal combustion motor, or to cause a change of the pitch of a propeller of a multi-engine airplane in the ease in which, following the stopping of an engine or principal motor, which likewise controls its pitch setting, the propeller should be placed in feathered position by the auxiliary motor and brought by the latter to the flying pitch before again bringing into driving operation the engine driving the propeller.

These installations advantageously comprise between the auxiliary electric motor and the drive shaft, an automatic clutch, as well as a speed reducer, to permit the employment of a highspeed electric motor which has light weight.

An object of the present invention is to provide a spur-gear reducer particularly, but not exclusively, applicable to such installations, this reducer being characterized by the fact that it is constituted by a double satellite wheel mounted eccentrically freely rotatably on the shaft, consisting oi. two external spur gears attached together driven by the auxiliary motor and made eccentric with relation to this shaft and with relation to two coaxial gears with internal teeth, with which the two sets of teeth of the satellite respectively mesh, one of these gears being fixed while the other is keyed on the output shaft to be driven.

Another object of the present invention resides in the centrifugal clutch employed to couple and uncouple the electric motor automatically with the driven shaft, this clutch being characterized by the fact that it is essentially constituted by three separate colinear pieces of shafting, aligned along the same axis, the first fixed to the shaft of the auxiliary motor, and which carries centrifugal wings provided with a toothed sector, the second constituting the intermediate shaft carrying at its end toward the auxiliary motor, a rack meshing with these toothed sectors, and at its opposite end carrying one of the clutch discs, the second clutch disc being engageable with the first and bein provided on the third v:piece connected to the device to be driven.

In the accompanying drawings:

Fig. 1 shows, in perspective, an embodiment of the present invention applied to the emergency control by an electric motor of the blades of a propeller;

Fig. 2 shows a top plan view of the same with parts in section; and

Fig. 3 shows a transverse section of the same, taken on the line 33 of Fig. 2.

Fig. 4 shows in front elevation with parts in section, a detail of the centrifugal clutch and the mounting of the intermediate shaft.

The reducer unit of my invention comprises a double satellite consisting of two gear wheels I and 2| of the same diameter, and attached together fixedly, as by cross bars 3|, 3|a, and having toothings of diiferent pitch, which are mounted freely rotatably on a bearing disc 2 which is eccentrically fixedly attached to the shaft 3 of the driving electric motor as by keying. This double satellite I, 2|, meshes respectively with two gears with internal teeth placed concentrically around the axis of shaft 3, one of these gears ll cooperatin with the wheel I, being an integral part of the base member of the reducer unit and casing 23, while the second gear with internal teeth 5, cooperating with the wheel 2|, forms part of a cylindrical member 24 which drives one of the plates 6 of a plate clutch 6-1, connecting the auxiliary electric motor to the shaft or members to be driven. Gears 4 and Ii have substantially the same tooth pitch.

The double satellite 2|, may be only slightly eccentric with relation to the internally toothed gear 4 which is fixed to the casing 23, and the internally toothed gear 5, which is rotatable, with which the double satellite meshes. In fact it is possible to cause meshing of a wheel with outside teeth in a wheel with inside teeth which has a diameter which is only slightly greater, on the condition of properly choosing the pressure angle as well as the diameters of the contouring of the teeth; it is desirable to adopt a minimum spacing of six teeth.

Because of this fact, a very large number ofteeth are in engagement, and for a given force to be transmitted, the modulus of the teeth can be chosen to be very small, which permits of obtaining a reducer unit of very small dimensions.

Furthermore, the slight degree of eccentricity permits causing the eccentric shaft to rotate at extremely high speed, since the rolling movements of the double satellite are only slightly subjected to the centrifugal force; furthermore, as in all hypocycloid gears, a part of this centrifugal force; will be balanced by the tooth reaction.

Since the auxiliary motor shaft 3 rotates at high speed, the driving motor can be small and light. The ratio of the reducer constituted by the wheels l, 2!, l, 5, mayhave values within very wide limits,

The centrifugal clutch utilizedto couple the reducer unit to the shaft or member to be driven, is constituted by a fork member 8, fixed to hearing disc 2 by connecting annular portion 33;. each of the two branches of this fork member 8, carrying a pivot 9 on which is pivoted a Wing or' fiyweight Ill. The two pivots 9 are placed-atan any reason, during the driving by the motor of the driving shaft 3, the driven member H is subjected to an external torque, under the action of external forces, and tends to assume a speed which is greater than the speed applied to it by the motor shaft 3, the helical spring [6 permits the grips of the clutch-plates 6, l, to jump apart a little, andccnsequently the clutchto slip.

In order to control with the; described device the orientation of the blades of a propeller, it

A issuflicient to cause to engage with the driven 7 wheel II, the one of the clutch discs normally equal distance from the motor axis, on the opposite sides of the latter, ina plane perpendicular to thisaxis, so that the wings 0r fiyweights l0, positioned near this axis when in a rest position, are raised under the action of centrifugal force, up to the intended position, when the motor has attained the determinedspeed at which it should be thrown in by engagement of its clutch. For the purpose of transmitting this movement of the wings or flyweights lilto the clutcheplate 6, in order to displace clutch-plate 6 axially to put it in engagement with the other c1utch-plate;'l, which is integral with the shaft or member II to be driven by the auxiliary motor, the wings or fiyweights l0 each carry a toothed sector l2, which meshes with a rack l3 fixed on the shaft 4,15, carrying the clutch-plate B. This latter shaft l4, I5, is made in two parts or sections, l4, l5,connecte,d-by the helical spring I6 andby a thrust-block H. The shaft section l4 carries the rack I3, one end of the; spring It being fixed to the block, while the clutch-plate Bis fixedbnthe shaftsection I5. Oneend of shaft l4 passes freely; through annular sleeve portion 33, and has a sliding fit inside a sleeve bearing 32 provided; lnanaxial bore inbearin disc 2. This latter section l5, is set into rotation by the gear 5 of the reducer unit through its cylindrical member- 24; by meansof a pin 22, without this pin pre-- venting; the axial displacement of the clutch plate- 6 under the pushing of the rack 13, or=under the action of the spring l8, tendingtoseparatethe two plates 6, l; of the clutch. V

The operation of the described assembly'isas; follows: The auxiliary motor, being declu-tched from the driven member II- which it is-to drive, is started up and engages only the one clutch plate 6, and its speed of rotation is reduced byi the reducer unit I, 4, 5. When the fork menu-- her; 8-, fixedly mounted on the motor; shaft 3", has attained a. predetermined operating. speed, the wings or flyweights Ill will have arrived in the position. shown in the drawing and their toothed v sectors-l2 will have displaced the rack l3'suiiiciently axiallytoward theleft, so that the push-l ing of the shaft section ll of the intermediate shaft; l4, l5, whichpush is transmitted through the: spring I 6, compresses the spring l t-and brings inter engagement the two plates 6, 7-; ofthe. clutcht The calibrated spring 16 is designedin aima-nenerto balance-the axial component of'the tangentialforce due tothe: motor torque. IfJfoif controlled by the main propeller engine of the aircraft to change the pitch of the propeller.

In order to serve as a starter for a combustion motor, it is-sufiicient to key the clutch plate 1 on the crank shaftof the combustion motor or any other part in driven engagement with the I latter;

It will be apparent to those skilled in the art that my invention is susceptible of modification toadapt the same to particular applications and conditions, and all such modifications which are within the scope of the appended claims, I consider to be comprehended within the spirit of my invention.

I claim:

1. In an auxiliary speed reducing motor control unit, a driving shaft, an intermediate-shaft, adriven shaft, a casing, said shafts being mounted coaxially separately insaid'casing, and said driving and driven shafts projecting through said casing, said casing being provided with a circular aperture having internal spur teeth concentric with said driving shaft, a circular eccentric bearing member fixedly carried by said driving shaft, a gyratory member comprising a pair of external spur gears of the same diameter having different pitches of their teeth andbeing fixedly attached together and rotatablymounted on said eccentric bearin member, a hollow cylindrical member rotatably mounted within said casingcontiguous thereto and having a circular aper-- ture surrounding said driving shaft'and of the samediameter and in register with said aperture in saidcasing and further being provided with internal spur teeth concentric with said drive shaft, said' external spur gearsrof said gyratory memberbeing or smaller diameter than said apertures in said casing and said cylindrical member, and respectively meshing with. said in-' ternal" spur teeth ofsaidaperturessaid intermediateshaft comprising a rack; adaptedfto apply axialidisplacing' pressure thereto, centrifugal displaceabl-e means carried by' said driving shaft and adapted under centrifugalactuationf to apply axialtthrust to saidirack, said intermediate shaft being. axially slidably keyed: to'said cylindrical member, anda plate. clutch having itsplates. respectively connected'to said intermediateshaft and. to, said driven shaft,: whereby upon attainmentby said driving shaft offarelatively high desired speed, said driven shaft is driven at a desired relatively low: speed;

' 2: A control unit according to claim 1, said;

centrifugal means"v comprising; a fork member terminally carriedby said'drivingshaf-t, and wing members ipivotally mounted on said'fork. member for: pivoting aboutwan axis perpendicular to the axis of: said driving shaft and comprising atoothed sector engaging" said rack.

3;:A: control unit according toclaim-1, at least six-of. saidexternal-spur teeth of each gear being in engagement-with said-internal spur' teeth.

'4; Aacontrol; unitzaccordingto claim 1-, said apertures of said casing and said cylindrical member havin substantially the same pitch of their said internal spur teeth.

5. A control unit according to claim 1, said intermediate shaft having a first section carrying said rack and a second section coaxial with and separate and spaced from said first section and axially slidably keyed to said cylindrical memher, and carrying a plate of said clutch, and axially deformable resilient means interposed between the adjacent ends of said first and second sections of said intermediate shaft.

6. A control unit according to claim 1, said intermediate shaft having a first section carrying 10 being fixed to said thrust block.

CAMILLE CHARLES DUCHAUSSOY.

No references cited. 

